Amerigo Wang | 2d5bf28 | 2009-06-03 21:46:09 -0400 | [diff] [blame] | 1 | /* Kernel module help for x86. |
| 2 | Copyright (C) 2001 Rusty Russell. |
| 3 | |
| 4 | This program is free software; you can redistribute it and/or modify |
| 5 | it under the terms of the GNU General Public License as published by |
| 6 | the Free Software Foundation; either version 2 of the License, or |
| 7 | (at your option) any later version. |
| 8 | |
| 9 | This program is distributed in the hope that it will be useful, |
| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | GNU General Public License for more details. |
| 13 | |
| 14 | You should have received a copy of the GNU General Public License |
| 15 | along with this program; if not, write to the Free Software |
| 16 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 17 | */ |
| 18 | #include <linux/moduleloader.h> |
| 19 | #include <linux/elf.h> |
| 20 | #include <linux/vmalloc.h> |
| 21 | #include <linux/fs.h> |
| 22 | #include <linux/string.h> |
| 23 | #include <linux/kernel.h> |
| 24 | #include <linux/bug.h> |
| 25 | #include <linux/mm.h> |
| 26 | |
| 27 | #include <asm/system.h> |
| 28 | #include <asm/page.h> |
| 29 | #include <asm/pgtable.h> |
| 30 | |
| 31 | #if 0 |
| 32 | #define DEBUGP printk |
| 33 | #else |
| 34 | #define DEBUGP(fmt...) |
| 35 | #endif |
| 36 | |
Amerigo Wang | 0fdc83b | 2009-06-03 21:46:19 -0400 | [diff] [blame] | 37 | void *module_alloc(unsigned long size) |
| 38 | { |
| 39 | struct vm_struct *area; |
| 40 | |
| 41 | if (!size) |
| 42 | return NULL; |
| 43 | size = PAGE_ALIGN(size); |
| 44 | if (size > MODULES_LEN) |
| 45 | return NULL; |
| 46 | |
| 47 | area = __get_vm_area(size, VM_ALLOC, MODULES_VADDR, MODULES_END); |
| 48 | if (!area) |
| 49 | return NULL; |
| 50 | |
Amerigo Wang | c398df3 | 2009-06-03 21:46:46 -0400 | [diff] [blame] | 51 | return __vmalloc_area(area, GFP_KERNEL | __GFP_HIGHMEM, |
| 52 | PAGE_KERNEL_EXEC); |
Amerigo Wang | 0fdc83b | 2009-06-03 21:46:19 -0400 | [diff] [blame] | 53 | } |
Amerigo Wang | 0fdc83b | 2009-06-03 21:46:19 -0400 | [diff] [blame] | 54 | |
Amerigo Wang | 2d5bf28 | 2009-06-03 21:46:09 -0400 | [diff] [blame] | 55 | /* Free memory returned from module_alloc */ |
| 56 | void module_free(struct module *mod, void *module_region) |
| 57 | { |
| 58 | vfree(module_region); |
Amerigo Wang | 2d5bf28 | 2009-06-03 21:46:09 -0400 | [diff] [blame] | 59 | } |
| 60 | |
| 61 | /* We don't need anything special. */ |
| 62 | int module_frob_arch_sections(Elf_Ehdr *hdr, |
| 63 | Elf_Shdr *sechdrs, |
| 64 | char *secstrings, |
| 65 | struct module *mod) |
| 66 | { |
| 67 | return 0; |
| 68 | } |
| 69 | |
Amerigo Wang | 0fdc83b | 2009-06-03 21:46:19 -0400 | [diff] [blame] | 70 | #ifdef CONFIG_X86_32 |
| 71 | int apply_relocate(Elf32_Shdr *sechdrs, |
| 72 | const char *strtab, |
| 73 | unsigned int symindex, |
| 74 | unsigned int relsec, |
| 75 | struct module *me) |
| 76 | { |
| 77 | unsigned int i; |
| 78 | Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr; |
| 79 | Elf32_Sym *sym; |
| 80 | uint32_t *location; |
| 81 | |
| 82 | DEBUGP("Applying relocate section %u to %u\n", relsec, |
| 83 | sechdrs[relsec].sh_info); |
| 84 | for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { |
| 85 | /* This is where to make the change */ |
| 86 | location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr |
| 87 | + rel[i].r_offset; |
| 88 | /* This is the symbol it is referring to. Note that all |
| 89 | undefined symbols have been resolved. */ |
| 90 | sym = (Elf32_Sym *)sechdrs[symindex].sh_addr |
| 91 | + ELF32_R_SYM(rel[i].r_info); |
| 92 | |
| 93 | switch (ELF32_R_TYPE(rel[i].r_info)) { |
| 94 | case R_386_32: |
| 95 | /* We add the value into the location given */ |
| 96 | *location += sym->st_value; |
| 97 | break; |
| 98 | case R_386_PC32: |
| 99 | /* Add the value, subtract its postition */ |
| 100 | *location += sym->st_value - (uint32_t)location; |
| 101 | break; |
| 102 | default: |
| 103 | printk(KERN_ERR "module %s: Unknown relocation: %u\n", |
| 104 | me->name, ELF32_R_TYPE(rel[i].r_info)); |
| 105 | return -ENOEXEC; |
| 106 | } |
| 107 | } |
| 108 | return 0; |
| 109 | } |
| 110 | |
| 111 | int apply_relocate_add(Elf32_Shdr *sechdrs, |
| 112 | const char *strtab, |
| 113 | unsigned int symindex, |
| 114 | unsigned int relsec, |
| 115 | struct module *me) |
| 116 | { |
| 117 | printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n", |
| 118 | me->name); |
| 119 | return -ENOEXEC; |
| 120 | } |
| 121 | #else /*X86_64*/ |
| 122 | int apply_relocate_add(Elf64_Shdr *sechdrs, |
| 123 | const char *strtab, |
| 124 | unsigned int symindex, |
| 125 | unsigned int relsec, |
| 126 | struct module *me) |
| 127 | { |
| 128 | unsigned int i; |
| 129 | Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr; |
| 130 | Elf64_Sym *sym; |
| 131 | void *loc; |
| 132 | u64 val; |
| 133 | |
| 134 | DEBUGP("Applying relocate section %u to %u\n", relsec, |
| 135 | sechdrs[relsec].sh_info); |
| 136 | for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { |
| 137 | /* This is where to make the change */ |
| 138 | loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr |
| 139 | + rel[i].r_offset; |
| 140 | |
| 141 | /* This is the symbol it is referring to. Note that all |
| 142 | undefined symbols have been resolved. */ |
| 143 | sym = (Elf64_Sym *)sechdrs[symindex].sh_addr |
| 144 | + ELF64_R_SYM(rel[i].r_info); |
| 145 | |
| 146 | DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n", |
| 147 | (int)ELF64_R_TYPE(rel[i].r_info), |
| 148 | sym->st_value, rel[i].r_addend, (u64)loc); |
| 149 | |
| 150 | val = sym->st_value + rel[i].r_addend; |
| 151 | |
| 152 | switch (ELF64_R_TYPE(rel[i].r_info)) { |
| 153 | case R_X86_64_NONE: |
| 154 | break; |
| 155 | case R_X86_64_64: |
| 156 | *(u64 *)loc = val; |
| 157 | break; |
| 158 | case R_X86_64_32: |
| 159 | *(u32 *)loc = val; |
| 160 | if (val != *(u32 *)loc) |
| 161 | goto overflow; |
| 162 | break; |
| 163 | case R_X86_64_32S: |
| 164 | *(s32 *)loc = val; |
| 165 | if ((s64)val != *(s32 *)loc) |
| 166 | goto overflow; |
| 167 | break; |
| 168 | case R_X86_64_PC32: |
| 169 | val -= (u64)loc; |
| 170 | *(u32 *)loc = val; |
| 171 | #if 0 |
| 172 | if ((s64)val != *(s32 *)loc) |
| 173 | goto overflow; |
| 174 | #endif |
| 175 | break; |
| 176 | default: |
| 177 | printk(KERN_ERR "module %s: Unknown rela relocation: %llu\n", |
| 178 | me->name, ELF64_R_TYPE(rel[i].r_info)); |
| 179 | return -ENOEXEC; |
| 180 | } |
| 181 | } |
| 182 | return 0; |
| 183 | |
| 184 | overflow: |
| 185 | printk(KERN_ERR "overflow in relocation type %d val %Lx\n", |
| 186 | (int)ELF64_R_TYPE(rel[i].r_info), val); |
| 187 | printk(KERN_ERR "`%s' likely not compiled with -mcmodel=kernel\n", |
| 188 | me->name); |
| 189 | return -ENOEXEC; |
| 190 | } |
| 191 | |
| 192 | int apply_relocate(Elf_Shdr *sechdrs, |
| 193 | const char *strtab, |
| 194 | unsigned int symindex, |
| 195 | unsigned int relsec, |
| 196 | struct module *me) |
| 197 | { |
| 198 | printk(KERN_ERR "non add relocation not supported\n"); |
| 199 | return -ENOSYS; |
| 200 | } |
| 201 | |
| 202 | #endif |
| 203 | |
Amerigo Wang | 2d5bf28 | 2009-06-03 21:46:09 -0400 | [diff] [blame] | 204 | int module_finalize(const Elf_Ehdr *hdr, |
| 205 | const Elf_Shdr *sechdrs, |
| 206 | struct module *me) |
| 207 | { |
| 208 | const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL, |
| 209 | *para = NULL; |
| 210 | char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; |
| 211 | |
| 212 | for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { |
| 213 | if (!strcmp(".text", secstrings + s->sh_name)) |
| 214 | text = s; |
| 215 | if (!strcmp(".altinstructions", secstrings + s->sh_name)) |
| 216 | alt = s; |
| 217 | if (!strcmp(".smp_locks", secstrings + s->sh_name)) |
| 218 | locks = s; |
| 219 | if (!strcmp(".parainstructions", secstrings + s->sh_name)) |
| 220 | para = s; |
| 221 | } |
| 222 | |
| 223 | if (alt) { |
| 224 | /* patch .altinstructions */ |
| 225 | void *aseg = (void *)alt->sh_addr; |
| 226 | apply_alternatives(aseg, aseg + alt->sh_size); |
| 227 | } |
| 228 | if (locks && text) { |
| 229 | void *lseg = (void *)locks->sh_addr; |
| 230 | void *tseg = (void *)text->sh_addr; |
| 231 | alternatives_smp_module_add(me, me->name, |
| 232 | lseg, lseg + locks->sh_size, |
| 233 | tseg, tseg + text->sh_size); |
| 234 | } |
| 235 | |
| 236 | if (para) { |
| 237 | void *pseg = (void *)para->sh_addr; |
| 238 | apply_paravirt(pseg, pseg + para->sh_size); |
| 239 | } |
| 240 | |
| 241 | return module_bug_finalize(hdr, sechdrs, me); |
| 242 | } |
| 243 | |
| 244 | void module_arch_cleanup(struct module *mod) |
| 245 | { |
| 246 | alternatives_smp_module_del(mod); |
| 247 | module_bug_cleanup(mod); |
| 248 | } |